pathartl

Accordion Archive Widget is exactly what the name implies. It recreates the stock archive widget, but this time around the widget is laid out as an accordion. It gives you the years of the archive, and then when the year is clicked it expands to show the months.
Development can be tracked at http://github.com/pathartl/accordion-archive-widget

Accordion Archive Widget

An archive widget that reconstructs the stock widget into an accordion by year with month children.

peterwsterling

A plugin to add a sidebar widget that presents a list of posts from “this Day/Week/Month” last year.
A feature of the sidebar that I like is the ability to “bring back” posts from the past. That is, the blog chronology constantly pushes great content into the archives. This sidebar widget, Last Year, brings posts from this day, week or month last year back to the fore!

Last Year Widget

A plugin to add a sidebar widget that presents a list of posts from "this Day/Week/Month" last year.

Accordion Archive Widget vs Last Year Widget